package model;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

//用于封装博客表的基本操作(增删改查)
public class BlogDao {
    //1. 往博客里面插入博客
    public void insert(Blog blog) {
        //JDBC基本代码
        Connection connection=null;
        PreparedStatement statement=null;
        try {
            //1.和数据库建立连接
            connection = DBUtil.getConnection();
            //2.构造sql语句
            String sql = "insert into blog values(null,?,?,?,now())";
            statement = connection.prepareStatement(sql);
            statement.setString(1, blog.getTitle());
            statement.setString(2, blog.getContent());
            statement.setInt(3, blog.getUserId());
            //3.执行sql
            statement.executeUpdate();
        }
        catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            //4.关闭连接,释放资源
            DBUtil.close(connection,statement,null);
        }

    }

    //2. 能够获得博客表的所有博客信息(用于博客列表页)
    public List<Blog> selectAll(){
        List<Blog>blogs=new ArrayList<>();
        Connection connection=null;
        PreparedStatement statement=null;
        ResultSet resultSet=null;
        try {
            connection=DBUtil.getConnection();
            String sql="select*from blog order by postTime desc";
            statement=connection.prepareStatement(sql);
            resultSet=statement.executeQuery();
            while(resultSet.next()){
                Blog blog=new Blog();
                blog.setBlogId(resultSet.getInt("blogId"));
                blog.setTitle(resultSet.getString("title"));
                //这里需要对内容截断(防止内容过程)
                String content=resultSet.getString("content");
                if(content.length()>50){
                    //取前50个字显示出来
                    content=content.substring(0,50)+"...";
                }
                blog.setContent(content);
                blog.setUserId(resultSet.getShort("userId"));
                blog.setPostTime(resultSet.getTimestamp("postTime"));
                blogs.add(blog);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        finally {
            DBUtil.close(connection,statement,resultSet);
        }
        return blogs;
    }

    //3. 能够根据博客id获取到指定博客内容(用于博客详情页)
    public Blog selectOne(int blogId){
        Connection connection=null;
        PreparedStatement statement=null;
        ResultSet resultSet=null;
            try {
                connection=DBUtil.getConnection();
                String sql="select*from blog where blogId=?";
                statement=connection.prepareStatement(sql);
                //这里的"1"代表上面的第一个问号.
                statement.setInt(1,blogId);
                resultSet=statement.executeQuery();
                //此处我们是使用主键作为查询条件,要么是1,要么是0.
                if(resultSet.next()){
                    Blog blog=new Blog();
                    blog.setBlogId(resultSet.getInt("blogId"));
                    blog.setTitle(resultSet.getString("title"));
                    blog.setContent(resultSet.getString("content"));
                    blog.setUserId(resultSet.getShort("userId"));
                    blog.setPostTime(resultSet.getTimestamp("postTime"));
                    return  blog;
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            finally {
                DBUtil.close(connection,statement,resultSet);
            }
        return null;
    }

    //4.根据博客id删除博客
    public  void delete(int blogId) {
        Connection connection = null;
        PreparedStatement statement = null;
        try {
            connection = DBUtil.getConnection();
            String sql = "delete from blog where blogId=?";
            statement = connection.prepareStatement(sql);
            statement.setInt(1, blogId);
            statement.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DBUtil.close(connection, statement, null);
        }
    }
}
